1. Field of the Invention
The present invention relates to printhead maintenance in an ink jet printer, and, more particularly, to a printhead capping assembly.
2. Description of the Related Art
Ink jet printers form an image on a print medium by selectively ejecting ink from one or more of a plurality of ink jet nozzles formed in a nozzle plate of an ink jet printhead. In order to maintain the printhead at an acceptable level of performance, ink jet printers typically include a maintenance station for performing scheduled maintenance operations and for providing a sealed environment for the printhead nozzle plate during periods of non-use.
One example of a maintenance station includes a movable maintenance sled including a printhead wiper and a printhead cap. The printhead wiper includes a blade edge for engaging the printhead nozzle plate to remove waste ink and contaminants that have accumulated on the printhead nozzle plate during printing. The printhead cap is moved by the maintenance sled from a non-contact position with respect to the printhead to a contact position with respect to the printhead in an attempt to provide a sealed environment around the ink jet nozzles of the printhead.
Typically, the cap is formed as a generally rectangular structure defined by four adjoining walls that extend vertically upwardly from a base, and is made from an elastomer, with an upper portion of the four adjoining walls defining a single sealing lip. Commonly, the elastomer cap is placed over the nozzle plate of the printhead in an attempt to provide a sufficiently humid environment to avoid undesirable drying and crystallization of ink on the printhead that may plug ink jet nozzles. Such a cap attempts to form an effective seal between the printhead nozzles and the ambient environment. However, where such an effective seal is formed, such a system may not provide adequate water containment evaporation.
What is needed in the art is a printhead capping assembly designed to maintain an effective seal around the printhead nozzle plate while providing adequate water containment evaporation at a desired evaporation loss rate.